In steam generators heating surface is normally disposed in the vertical rear path leading from the furnace. This surface can be superheater, reheater or economizer tube panels, and is made up of sinuous tubes having parallel horizontal runs through which the fluid being heated flows. In large steam generators, it is necessary to support these horizontal runs in a manner which will permit unequal thermal expansion to take place in the various horizontal tube runs, without placing undue stress in the tubes.